Resilient mounting for an outboard motor



. 8, 1959 r E. c. KIEKHAEFER RESILIENT MOUNTING FOR AN OUTBOARD MOTOR 3Sheets-Sheet 1 Filed June 3, 1955 IN VEN TOIOQ. EZZMH? c. K/EKMHER H61.BY 5: d) :2

,4 TTORNE V 'E. C. KIEKHAEFER RESILIENT MOUNTING FOR AN OUTBOARD MOTOR 3Sheets-Sheet 2 Filed June 3, 1955 INVENTOR. EZMEP l. KIEKHAEFER ATTORNEYDec. 8, 1959 E. c. KIEKHAEFER RESILIENT MOUNTING FOR AN OUTBOARD MOTORFiled June 3, 1955 3 Sheets-Sheet 3 INVENTOR. HMER [.K/EKHAfFER flv. [1MM ,4 T TORNEV United States Patent RESILIENT MOUNTING FOR AN OUTBOARDMOTOR Elmer Carl Kiekhaefer, Cedarburg, Wis.

Application June 3, 1955, Serial No. 512,940

6 Claims. (Cl. 11518) boat.

Heretofore, shock mountings have been developed for cushioning thetorque vibration of the power head and propeller unit from the transombracket and boat. Such mountings, however, do not prevent other types ofvibration from being transmitted to the transom bracket and boat.Applicants invention provides a novel and improved means for resilientlysuspending the outboard motor unit comprising the power head, driveshaft and lower unit to vibrationally isolate the outboard motor unitfrom the supporting bracket and boat.

It is therefore an object of the present invention to suspend or floatan outboard motor unit for freedom from torque vibration withouttransmitting any of such vibrations to the supporting bracket or boatand without in any way interfering with the perfect control of thepivotal steering movement of such motor.

Another object of the invention is to provide novel means forresiliently suspending the outboard motor unit within a supportingmember. 7

Another object of the invention is the provision of novel resilientmeans of simple construction requiring fewer parts and less machiningthan prior known means for vibrationally isolating the outboard motorunit from the boat and supporting member.

Another object of the invention is to provide a resiliently suspendedoutboard motor unit in which the dynamic forces developed thereby areresisted primarily by the supporting resilient means.

Another object of the invention is the provision of novel resilientmeans for supporting the outboard motor unit wherein impact resultingfrom the outboard motor propeller striking an obstruction is absorbed bysaid resilient means.

Objects and advantages other than those set forth above will be apparentfrom the following description when read in connection with theaccompanying drawing, in which:

Fig. l is a side elevation view shown partially in section of anoutboard motor embodying the invention;

Fig. 2 is a side elevation view of a part of an outboard motor embodyingthe invention;

Fig. 3 is a front view of the structure shown in Fig. 2;

Fig. 4 is a section view taken along line 4-4 of Fig. 2;

Fig. 5 is a view shown partially in plan and partially in section takenalong line 55 of Fig. 3;

Fig. 6 is an enlarged section view taken along line 6-6 of Fig. 4; and

Fig. 7 is a side elevation view of an outboard motor embodying theinvention showing a force diagram of thrust forces acting thereon.

As shown in the drawings, a preferred embodiment of the invention isillustrated as applied to'an outboard motor ice 1 comprising a hollowdrive shaft housing 2 for enclosing a drive shaft 5, a gear housing 3 orlower unit connected to the drive shaft housing 2 and-carrying apropeller 4 at the lower end thereof, and attachment means 6 forattaching the outboard motor 1 pendently to the transom 7 of a boat, notshown. The vertical drive shaft 5 may be considered to be at or near tothe center of gravity of the outboard motor unit, although in some casesthe center of gravity may be rearwardly of the shaft.

The attachment means 6 or support member comprises a clamp bracket 8having a generally L-shaped swivel bracket 9 pivotably connected theretoby means of a bolt 11 for pivotal movement in a vertical plane. Theclampbracket 8 is shown as a substantially U-shaped clamp adapted to engageover the upper edge of the transom 7 and carrying a clampingscrew 12 atthe lower end thereof for engaging the inside of the transom '7 to clampthe transom 7 between the end of thescrew 12 and a portionof the clampbracket 8. The swivel bracket 9 includes a vertically extending bushing13 in register with openings 14 provided in the upper and lowerbifurcated members 18, 19 which together with the connecting hollowpivot pin 17 comprise a yoke'member 16 forming a part of the supportmember. The yoke member is pivotably connected to the swivel bracket formovement in a horizontal plane with the hollow pivot pin 17 passingthrough bushing 13. The pin 17 isconnected to the members 18, 19 bymeans of a press fit 'to'solidly join the up per and lower members 18,19. A pair of laterally spaced bolts 20 as shown in Fig. 4' pass throughfore and aft horizontally extending openings '21 in the lower member 19while a pair of laterally spaced studs 22 as shown in Fig. 5 parallelthe bolts 20 and engage tapped openings in the upper member'l-Sto-cornplete the yoke member 16.

The drive shaft housing 2 as shown inFig. 1 comprises a hollow castmemberhaving an upper flared region 23, an intermediate convergentregion 24, and a lower portion 26 which extends outwardly, bothforwardly and rearwardly. The drive shafthousing 2 is provided with astreamlined rear portion 27 as shown in Fig. 4 to reduce the resistanceof the housing 2 while.moving through water, and the front portion 28 ofthe housing 2 opposite from yoke member 16 is substantially planar.

The drive shaft housing 2 is attached and spaced from the yoke member 16by means of resilient members comprising annular rubber members 29 asshown in Figs. 4, 5 and 6. The resilient members 29 are each providedwith inner and outer annular vmetal cylinders 31, 32 bonded thereto asshown in Fig. 6. .The inner metal cylinder 31 is mounted on acorresponding finger projecting from yoke member 16, here illustrated asa bolt 20 or stud 22 and the outer metal cylinder 32, in the case of thelower member 19, is seated within an annular groove 33 provided inrecess 34 of the housing 2. YA metal cap 35 of semi-circular crosssection is secured to the housing 2 by means of screws 36 and togetherwith recess 34 forms a cavity within which the resilient member 29 isdisposed. In the case of the upper member 18, the outer metal cylinder32 of the resilient member 29 is seated within an annular groove 37formed by a splithollow cylindrical member 38 which is secured to thedrive shaft housing 2 by means of bolts 39 passing therethrough andengaging threaded openings, not shown, in the housing 2. The inner metalcylinders 31 of the rubber members 29 are secured to the lower member 19between the heads of'the respective bolts 20 and the member19 by meansof nuts 41. In the upper member 18 the inner metal portions 31 aresecured between the member 18 and respective nuts 42 threaded on thestuds 22. Interposed between the nuts 42 and the resilient members 29 ofthe upper member 18 are resilient cushion rings 43 adapted to engage a Apower head 45 as shown inFig. l', the drive shaft .housing2 upon whichthe power head 45 is mounted, and the lower unit or gear housing 3 forman outboard motor unit that is completely supported by the yoke member16 of the attachment means 6 by means of the resilient members 29.Therefore, the weight of this outboard motor unit, the forces developedby the'action of the power head 45 and the thrust developed by thepropeller 4 are resisted bythe vertically spaced resilient members 29.

In order to permit substantially complete freedom of movement of theoutboard motor unit relative to the yoke member 16, a flexible shiftcontrol rod 46 as shown in ,Fig. l is provided passing through the pivotpin 17 to connect the shift control 47 carried by the power head 45 tothe portion of the shift control 48 carried by the gear housing 3.

The proper positioning and dimensioning of the resilient members 29 maybe readily calculated by resorting to a force-moment diagram as shown inFig. 7. Assuming that the maximum propeller thrust F acting through thepoint C is 100 pounds and the lower resilient member 29 is positioned atB so that the distance S be tween the upper resilient member 29positioned at A and the lower member at B is equal to the distance Sbetween the lower member at B and the point C, the forces F and F may becomputed as follows:

Taking force'moments about the point B:

silient members 29 positioned at B must be chosen ofproper strengthcharacteristics-and dimensions to withstand a thrust force of 200 poundswhereas the resilient members 29 positioned at A need only be strongenough to resist a force of 100 pounds. 7

Where the center of gravity of the outboard motor unit is to the rear ofthe resilient members 29, the weight of the motor will generally add tothe forces referred to above. It is, therefore, desirable to dispose theresilient members on opposite sides of the center of gravity with atleast some part of the members in the transverse plane containing thecenterof gravity; Intheillustrations, it will be noted that the members29 are disposed laterally of the drive shaft 5, whichin this instanceisvery close to the vertical transverse plane of the center of gravity,

Although only one embodiment has been illustrated and described, it willbe apparent to those skilled in the art that various changes andmodifications may be made therein without departing from the spirit ofthe'invention or from the scope of the appended claims.

It is claimed and desired to secure by.Letters Patent: 7

operating position, said support member means being provided with foreand aft extending and laterally spaced fingers to form a substantiallyU-shaped portion, the housing of said unit being disposed generallyrearwardly of said support member means and fore and aft extendinghousing recesses therein aligned with and concentric to said fingers, aplurality of resilient means each comprising an annular rubber elementbonded between inner and outer cylinders and interposed between saidsupport member means and said housing with the inner cylinder of one ofsaid resilient means being mounted on each of said fingers and the outercylinders thereof engaging the wall of the corresponding recessesprovided in the housing, said resilient means comprising the soleconnection between said unit and said support member means to providefor relative movement of said unit with respect to said support membermeans to vibrationally isolate said unit from 7 said support membermeans.

2. The combination of claim 1 wherein stop means associated with saidfingers are provided for limiting the deflection of said resilientmeans.

3. In an outboard motor, the-combination of: a support member mountableon the transom of a boat, a yoke member carried by said support memberand being pivotable'relative to the support member about a substantiallyvertical axis when the power unit is in normal operating position, apair of horizontally extending, laterally spaced and aligned fingersprojecting rearwardly from the respective upper and lower ends of saidyoke member, a 7

power unit comprising a power head and a drive shaft housing supportingsaid head, the housing of said unit being disposed generally rearwardlyof said yoke member and having fore and aft extending semi-circularrecesses therein aligned with each of the lower fingers of the yokemember, a semi-circular cap member mounted on said housing in registerwith each of said recesses to form first cylindrical cavities in saidhousing for receiving the corresponding'lower fingers, of said yokemember, fore and 'aft extending annular members carried by said housingand forming second cylindrical cavities for receiving the respectiveupper fingers of the yoke member, and a plurality of annular rubberelements each encased in an inner and outer metallic sleeve interposedbetween the yoke member and said housing with the inner sleeve of one ofsaid resilient means being mounted on each of the yoke member fingersand the outer sleeves thereof engaging the wall of the correspondingcavities in said housing, said elements comprising the sole connectionbetween the power unit and yoke member to vibrationally isolate saidunit from said yoke member. 7

4. The combination set forth in claim 3 wherein the upper fingers ofsaid yoke member are provided with resilient stop means adapted toengage a shoulder provided in the respective cavities for said fingersto limit the deflection of the corresponding rubber elements.

' 5. In an outboard motor, a'power unit including a drive 7 shafthousing, means for supporting the power unit on a boat and including asupport member pivotally movable about a substantially vertical axiswhen the power unit is in normal operating position and disposedforwardly of the unit, upper and lower laterally spaced and alignedfinger means extending rearwardly from said support member, said driveshaft housing being disposed generally rearwardly of said support memberand having fore and 'aft extending recesses therein aligned with andconcentric power head and a housing member supporting said head,

means for'supporting the power unit on a boat and in-,

cluding a support member pivotally movable about a substantiallyvertical axis when the power unit is in normal operating position anddisposed forwardly of said power unit, laterally spaced and alignedfinger means extending in a fore and aft direction between the housingmember and support member and connected to one of said members, saidfinger means being received in fore and aft extending cylindricalrecesses provided in the other of said members, and an elongated annularresilient element disposed between each of the respective finger meansand the wall of the corresponding recess, said elements comprising thesole connection between the power unit and the support member tovibrationally isolate the unit from the support member.

References Cited in the file of this patent UNITED STATES PATENTS IrgensAug. 11, 1931 Irgens Oct. 31, 1933 Linthwaite May 24, 1938 LinthwaiteAug. 23, 1938 Karey June 13, 1944 Kiekhaefer June 23, 1953 Irgens et a1Apr. 3, 1956 FOREIGN PATENTS Italy Mar. 22, 1934

